branding: move logo into database

initially, i tried to put this in the current value field but that
is TEXT and has a size limit of 64K. TEXT also stores things with
character encoding, so we have to stash it as base64

src/settingsdb.js

@@ -3,9 +3,11 @@
 'use strict';
 
 exports = module.exports = {
-    get: get,
-    getAll: getAll,
-    set: set,
+    get,
+    getAll,
+    set,
+    getBlob,
+    setBlob,
     _clear: clear
 };
 
@@ -14,6 +16,7 @@ var assert = require('assert'),
     database = require('./database.js');
 
 const SETTINGS_FIELDS = [ 'name', 'value' ].join(',');
+const SETTINGS_BLOB_FIELDS = [ 'name', 'valueBlob' ].join(',');
 
 function get(key, callback) {
     assert.strictEqual(typeof key, 'string');
@@ -47,6 +50,31 @@ function set(key, value, callback) {
     });
 }
 
+function getBlob(key, callback) {
+    assert.strictEqual(typeof key, 'string');
+    assert.strictEqual(typeof callback, 'function');
+
+    database.query(`SELECT ${SETTINGS_BLOB_FIELDS} FROM settings WHERE name = ?`, [ key ], function (error, result) {
+        if (error) return callback(new BoxError(BoxError.DATABASE_ERROR, error));
+        if (result.length === 0) return callback(new BoxError(BoxError.NOT_FOUND, 'Setting not found'));
+
+        callback(null, result[0].valueBlob);
+    });
+}
+
+function setBlob(key, value, callback) {
+    assert.strictEqual(typeof key, 'string');
+    assert(value === null || Buffer.isBuffer(value));
+    assert.strictEqual(typeof callback, 'function');
+
+    database.query('INSERT INTO settings (name, valueBlob) VALUES (?, ?) ON DUPLICATE KEY UPDATE valueBlob=VALUES(valueBlob)', [ key, value ], function (error) {
+        if (error) return callback(new BoxError(BoxError.DATABASE_ERROR, error)); // don't rely on affectedRows here since it gives 2
+
+        callback(null);
+    });
+}
+
+
 function clear(callback) {
     database.query('DELETE FROM settings', function (error) {
         if (error) return callback(new BoxError(BoxError.DATABASE_ERROR, error));